Posted
by
CmdrTacoon Monday June 15, 2009 @12:12PM
from the sounds-like-my-chili dept.

KentuckyFC writes "Black holes are thought to form when a star greater than 4 times the mass of the Sun explodes in a supernova and then collapses. The force of this collapse is so great that no known force can stop it. In less massive stars, the collapse cannot overcome so-called neutron degeneracy, the force that stops neutrons from being squashed together. Now a Russian physicist says another effect may be involved. He points out that quantum chromodynamics predicts that when neutrons are squashed together, matter undergoes a phase transition into "subhadronic" matter. This is very different from ordinary matter. In subhadronic form, space is essentially empty. So the phase change creates a sudden reduction in pressure, forcing any ordinary matter in the star to implode into this new vacuum. The result is a massive increase in temperature of this matter that creates a "burning wall" within the supernova. And it is this burning wall that stops the formation of a black hole, not just the degeneracy pressure of neutrons. This should lead to much greater energies inside a supernova than had been thought possible until now. And that's important because it could explain the formation of high energy gamma ray bursts that have long puzzled astrophysicists."

I mean, this is more of synthesis of existing observations rather than *new* observations, but it's still science.

It's taking unexplained observations and incorporating those observations into better theories that fit the data. I'm not an astrophysicist, and this still seems like it's just an hypothesis, but I guess I don't see where the problem is.

There's nothing wrong with faith per se, except when it interferes with observable reality. But it's not faith because it's recognized as one of many possibilities and has a probability attached to it.

What you're seeing is that this possibility is the most probable, which is why it is favored over the other myriad of possibilities. But when some new data comes along, this idea may be strengthened or weakened, and it may eventually lose its favored status to another possibility. Sometimes, but relatively rarely, a possibility is so probable that it becomes generally irrefutable (but the minutae are usually still in the works), in which case, it becomes theorem a.k.a. fact.

Of course, even facts can be changed with new data. "Refined" is probably the correct term. Facts don't get turned upside down, but they may get marginalized, or slotted into a larger, more general fact, or pieces may be replaced with better ideas. For example, gravity being the 4th fundamental force is a fact, but the mechanism behind gravity isn't understood. So some data may come along to explain gravity, or to turn gravity into one of the other 3 fundamental forces, or to make gravity only a small part of a much larger 4th fundamental force. But since no such data exists as of now, gravity remains as it is.

In other words, he just put forth a possible explanation without any hard data to back it up. People have done the same in the past, only to have the observations go against their hypotheses. Building a hypothesis is only half the battle; you still need to gather evidence to support it.

Well, the alternatives to dark matter/energy suck. Either there's more matter and energy out in the universe than we can observe directly, or gravity doesn't work the same on large scales as it does on small scales. Dark energy is hypothesized because we have not observed anything to account for the accelerating expansion of the universe.

The theories of dark matter and dark energy require the fewest assumptions, and best explain the observed phenomena, so it's they're working theories du jour. We don't like

He was pointing out that the statement "hypothesis are usually created to fit the data, not the other way around" was utter non-sense. Ideally, that's true, but we end up with observations that should not exist based on everything else we observe, it's a thorn in the side and it needs an explanation. Thus what are essentially still just hypothesis get called theories because a) observations necessary have so far been impossible and b) the

When I was an undergrad, I worked on CASA, the Chicago Air Shower Array. It was a big array of detectors in the Utah desert, designed to identify point souces of ultra-high energy gamma ray bursts and get more information about the showers of particles they create when they hit the atmosphere.

It's nice to see a model that could conceivably give an idea of how gamma ray bursts happen. In 1988-89, there really weren't any very good candidates. The problem was interesting enough to get James Cronin, who had won a Nobel Prize with Val Fitch for their discovery of a certain kind of symmetry violation in particle physics, interested in experimental astrophysics. He was one of the principal scientists on the project. And he even did some manual labor, like helping with wrapping detectors. I remember him eating the lunch he had brought from home and talking to me about the health benefits of garlic as we worked on preparing detectors one day.

Each box had four detectors in it, each detector made of a piece of scintillator with a big photomultiplier attached, all wrapped in black to make it light-tight. In addition to an identifying number, the grad students gave each box a name. Some were named for blues musicians, for example. At some point, the undergrads working on the project started expressing creativity by using made-up names to sign the detectors we had prepared and tested. To this day I wonder if Cronin ever saw the one I had signed as "Cronan the Barbarian."

However, I have a lot of speculation on any theory especially those about space where we have yet to really explore and travel, where someone assumes a few laws about existence of such an anomaly, and therefor think themselves expertson the subject. I tend to think it is a work in progress until we can provide 100% proof that wood floats in water, or ice melts into water, etc....we have no proof of anything concerning black holes, because we don't even have one near us to view and analyze......!

"I tend to think it is a work in progress until we can provide 100% proof that wood floats in water, or ice melts into water, etc...."

Not surprising you think it's "a work in progress", that is what it is supposed to be. Proof is for axiomatic systems. Science offers a way to make usefull predictions of the future with various degrees of certainty, that certainty never reaches 100% as it does in maths (and dare I say religion).

Sure you can demonstrate a piece of wood floats but that is not "100% proof

What?! No! The heart of science is not fitting hypotheses to data. That's the sort of dangerous fallacy that produces Aristotle's "science", and in fact what dangerous fundamentalists thrive on. The thing that sets science apart is rigorous, repeatable empirical testing of not previously observed predictions.
Not to say that the hypothesis in the article isn't exciting, but the already raising it up as a shining example of scientific triumph starts down a path I find terrifying.

But you realize that faith is not an inherently religious concept. You have faith that science will explain things like the "Big Bang" and the "cause" of gravity. In fact, you have faith that science is a useful tool in the first place. What if all of our observations are based on a lie perpetrated by an all-powerful trickster (see Descartes)? Or perhaps reality is merely a series of shadows projected on a cave wall in front of a captive audience (see Plato).
Attempting to set science above religious d

That is what science is about. Revelation based on fact, not faith. At the end of the day I think it's a lot more rewarding, although a lot harder to come by.

Many scientific revalations were based on faith, the assumptions a scientist makes when creating their theory. Unlike blind-faith commonly associated with religion, science allows those faith based assumptions to be tested. Ptolemy created a scientifically valid geo-centric model of the solar system, in that it could accurately predict the motion of

If we ever found a way to accelerate neutrons, that might work. Trouble is, neutrons have no charge, and our colliders need a charge to grab on to. We have neutron sources, in the form of fissioning elements, but there's no way to get those neutrons to go around in a circle. So the usual trick of slamming particles into each other at near-lightspeed isn't possible. I suspect that testing this particular idea won't be possible until we understand so much about particle physics that we don't even need to

One could suggest using a gravity powered accelerator, though that might be a tad difficult. However, from what I understand you should be able to use other hadrons to investigate collapse into subhadronic matter, which is precisely what LHC was built to play with.

Attach them to some protons and fling the combined nuclei. How bout a 1:1 ratio, good ole deuterium.

Shouldn't it be possible to see this effect in n-n collisions, much as quark effects were discovered?

If colliding deuterium ions into bulk deuterium doesn't work, fling the accelerated ions at a target just right to break off the proton and let the neutron fling onwards into a "bucket of neutrons" from a source or a reactor. Reaction rate will be pretty slow, but if you got all day to let it run, thats OK?

In a neutron star, of course, it's neutrons undergoing the hypothesized process, but is there any reason why protons wouldn't under the right conditions? If we could observe this happening with any subatomic particles, it would be sufficient to prove this is what happens to matter under those conditions.

Create some subhadronic matter and see if it causes a region of space with lower pressure than the surrounding space. As a bonus, measure the temperature of that space before and after the pressure vacuum stabilizes.

Create some subhadronic matter and see if it causes a region of space with lower pressure than the surrounding space. As a bonus, measure the temperature of that space before and after the pressure vacuum stabilizes.

Show all work. Write legibly in #2 pencil or blue or black permanent ink. Do not write on test booklet. Do not start until signaled to do so by your proctor. Destruction of the earth will result in automatic failure. You will have three (3) hours.

That's an interesting article. New QCD phases have been postulated for quite a while (colour superconductors etc.) but last time I talked to an expert on it and asked whether it could account for the missing energy in a Supernova (currently SN models seem to fizzle more than explode) his reply was that the phase change was too slow to release enough energy to help the SN go bang. I'll have to read the paper to see it this idea addresses this issue.

Reading comprehension FAIL: exactly the opposite is true. Our star will NOT supernova and form a black hole because our sun is EXACTLY one solar mass (being the star that scale is based on) which is less than eight solar masses.

Our star will NOT supernova and form a black hole because our sun is EXACTLY one solar mass

And that PROVES the existence of God. I mean, what is the chance that OUR sun is EXACTLY one solar mass? There must be hundreds of suns in the universe and we got the ONLY exact one because WE are Gods CHOSEN.

Sorry, but by the time our sun has passed through it's red giant phase it will be considerably LESS than one solar mass.

(I've always wondered at what point in a stars life they count it's weight for that phrase. Possibly they're uncertain enough about the exact value that it doesn't matter, but I think the sun is expected to shed something approximating 1/4 of it's mass during the red giant phase, so that's a lot of uncertainty.

OTOH, I'm definitely NOT a astrophysicist, and I might be off in how much mass

The phrase that stuck out for me was, 'a phase transition into "subhadronic" matter'. While I certainly recognize the need for new vocabulary when a new model/theory/phenomenon is described or discovered, this particular phrase, "subhadronic matter", gives me Star Trek Voyager flashbacks.

"Captain, the Borg are pulling us in!"

"Lt. Torres, can you reroute the power to the deflection array dish, and invert the signal to send out a subhadronic matter stream? That should disrupt the tractor beam long enough for

Great! Let's use the scientific method to test this hypothesis. Oh wait, nevermind.

Sorry, but it's hard not to be cynical about astrophysics. Dark matter sounds like something invented by a writer for a Japanese cartoon series, and the scientific explanation sounds about as likely to be true.

Then come up with a better idea of why galaxies move at the same rate on the outer edge that they do towards the center. That is what Dark Matter is all about, I'm not sure what Japanese cartoon series you're talking about but the idea from Dark Matter came from observations.

The same way dimensions on the quantum scale fold in on themselves, it is possible that space itself is higher dimensional, and we see a subset of the dimensions. Thereby, on a galactic scale, there are more dimensions, which can easily screw the math to make gravity more powerful on a larger scale.

That's exactly what we will do. This hypothesis will be quantified into making predictions about what we will see from supernovae and gamma-ray bursts (and perhaps other events). We will then plan and conduct observations of these events and see if the predictions of this hypothesis are consistent with the new data.
A lot of interesting ideas like this come out but then stall for a while as people try translate qualitative ideas into quantitative predictions. Once that happens we can go out and test the

Sorry, but it's hard not to be cynical about astrophysics. Dark matter sounds like something invented by a writer for Sailor Moon the Japanese cartoon series, and the scientific explanation sounds about as likely to be true.

Great! Let's use the scientific method to test this hypothesis. Oh wait, nevermind.

Sorry, but if you don't understand how to test these hypotheses using the scientific method, you clearly don't understand science well enough to have a clue. What you really mean is, it's hard not to be cynical when you don't have a clue and can't be bothered to get one.

There are a lot of very difficult theoretical problems involved in trying to describe the structure of neutron stars. The classic picture of a star made of nothing but neutrons is probably not quite right, and is possibly qualitatively wrong in important ways. There's supposed to be an upper limit on the mass of a neutron star, and the theoretical uncertainties get greater as you get closer to this mass limit. E.g., it's possible that you get quark stars. We just don't know, because we don't know the behavior of the strong and weak nuclear forces with sufficient precision to be able to extrapolate to these extreme conditions.

Given all that uncertainty, which has existed for many decades, it's not at all surprising to me that there's a corresponding uncertainty about the conditions under which a neutron star is or isn't unstable with respect to collapse into a black hole. The paper [arxiv.org], which is linked to from the end of the Technology Review article, is pretty heavy going. My field is nuclear physics, not relativistic astrophysics, and I had a hard time understanding it. The author's English is also pretty hard to understand, so it's hard to tell exactly what he's saying his conclusions are. But if you look at the end, he seems to be suggesting that black holes actually do not form.

I wonder to what extent existing observations constrain this idea. For instance, we know that the Sagittarius A* object at the center of our galaxy has a mass of at least 3.7 million solar masses and a radius of less than 6.25 light-hours.
It would be interesting to know what he proposes this object is, if he says it's not a black hole.

Sagittarius A* object at the center of our galaxy has a mass of at least 3.7 million solar masses

What the author is refering to is stellar mass black holes, ie. black holes that form from core collapse in star. The Supermassive black holes such as the one in our galaxy are a different beast entirely.